1. Field of the Invention
The present invention relates to a wind turbine generator comprising a nacelle supported on a tower so as to perform yaw control, or a plurality of blades which are supported on a hub so as to perform pitch control of the blades, with a gear transmission mechanism provided for controlling the pitch of the blade or the yaw of the nacelle, and a method of controlling the wind turbine generator. More specifically, the present invention relates to a wind turbine generator with a gear transmission mechanism comprising pitch wheels provided on a shaft side to be controlled and pinion gears provided so as to mesh with the gears, and the controlling method thereof.
2. Description of the Related Art
In reference to FIG. 11, a schematic structure of the wind turbine generator is explained. In FIG. 11, the wind turbine generator 100 comprises a tower 102 installed upright on a foundation B, a nacelle 102 provided on a top end of the tower 102, a hub 106 fixed to the nacelle 104, and a plurality of blades 108 fixed to the hub 106.
The nacelle 104 supports the rotor hub 106 and houses a rotation shaft 110 and a generator 112 therein. The rotation shaft 110 transmits the torque from the rotor hub side to the generator side.
In this type of wind turbine generator, Patent Documents listed below disclose to perform the pitch control of the blades 108 with respect to the rotor hub 106 or the yaw control of the nacelle 104 with respect to the tower 102 via the gear transmission mechanism.
For instance, a variable pitch mechanism disclosed in Patent Document 1 is explained in reference to FIG. 12. The variable pitch mechanism 120 comprises an internal gear 122a formed on an inner circumference of a blade ring 122 of the blade 108, and a gear reducer 136 for transmitting the drive power from the motor driving the pinion gear 124. The pinion gear 124 is rotated so as to change the pitch of the blade 108.
Moreover, Patent Document 2 discloses a power transmission mechanism of a planetary gear type arranged such that a plurality of shafts are provided around a pitch shaft center of the blade at a base of the blade and planetary gears are arranged therein supported rotatably. The planetary gear revolves and rotates so as to transmit the motion of the blade to the rotor and also the blade pitch is controlled by controlling the rotation of the planetary gear by a rotation member of a ring shaped motor.    [Patent Document 1] JP2003-222070A    [Patent Document 2] US2009/0016885A1